Biomedical subjects

A G Shindler

Publications and source records attributed to A G Shindler.

4 recordsLinked to original sources

PubMed1985

Language disintegration in dementia: effects of etiology and severity.

The speech characteristics on a standardized picture description task of 26 subjects with presumed senile dementia of the Alzheimer type (SDAT) and 13 subjects with stroke-related dementia (SRD) were compared to 15 normal subjects over age 59 years. Compared to the normal subjects, the dementia subjects used fewer total words, fewer unique words, fewer prepositional phrases, fewer subordinate clauses, and more incomplete sentence fragments. Lexical deficits tended to be more severe than syntactic ones, confirming prior suggestions that lexicon is more vulnerable to disruption in dementia than syntax. Greater dementia severity among the SDAT subjects was associated with marked difficulties in accessing the mental lexicon (increased use of empty words, indefinite anaphora, and pronouns). Greater dementia severity in the SRD subjects was associated with laconic speech that was syntactially less complex. Diffuse brain injury (as typified by SDAT) appears to disproportionately affect lexicon whereas multifocal injury (as typified by SRD) has a disproportionate effect on syntax (assuming that focal lesions of the posterior language zone have been excluded). The speech characteristics of the mild SDAT subjects showed similarities to those of anomic or semantic aphasia whereas the speech of the more advanced SDAT subjects showed similarities to Wernicke aphasia or transcortical sensory aphasia. The speech of the subjects with more severe SRD showed some similarities to Broca aphasia. The most important nonlinguistic deficit in both the SRD and the SDAT groups was a failure to make relevant observations during the picture description task. Perseverations were present in the speech of both the SRD and SDAT subjects, whereas aposiopesis, logorrhea, and palilalia were more typical of the SDAT subjects. Laconic speech was more characteristic of the SRD subjects.

Aged↗

PubMed1984

Intrusions and perseverations.

Twenty-two subjects with presumed senile dementia of the Alzheimer's type (SDAT), twenty-two with dementia other than SDAT, twenty with aphasia, and seventeen healthy controls over 50 years of age were examined for intrusions and perseverations. Perseverations were defined as the immediate inappropriate repetition of a prior response whereas intrusions were defined as the inappropriate repetition of prior responses after intervening stimuli. Intrusions and perseverations occurred in demented and aphasic subjects, but were rare in controls. Intrusions occurred most often in SDAT or Wernicke aphasia, but also in dementia other than SDAT. Intrusions were not correlated with dementia severity. Intrusions are a useful sign of dementia, but they cannot be considered pathognomonic of SDAT. They appear to arise when subjects are unable to access correct responses from long-term memory and instead substitute erroneous responses selected from short-term memory. Perseverations were most common in the Wernicke aphasics and subjects with dementia due to communicating hydrocephalus. Although frontal lobe dysfunction is prominent in communicating hydrocephalus, it is absent in cases of Wernicke aphasia. Thus, we have confirmed prior suggestions that perseveration can occur in the absence of frontal lobe injury. Failure to self-monitor speech as well as an inability to change mental set probably plays an important role in the genesis of perseverations. There was no statistically significant correlation between dementia severity and number of perseverations. Low correlations were found between intrusions and perseverations suggesting that these seemingly similar behaviors are distinct and are probably produced by separate neuropsychological mechanisms.

Age Factors↗

PubMed1984

Altered patterns of word associations in dementia and aphasia.

The word associations of 38 demented, 17 aphasic, and 22 normal subjects were studied. Both normal and brain-injured subjects appear to make judgments about the grammatical class of the word stimulus. Certain stimulus words (especially nouns and adjectives) elicit paradigmatic responses whereas other words (especially verbs and adverbs) elicit syntagmatic responses. The mechanism producing syntagmatic responses seems relatively resistant to deterioration in dementia or aphasia. However, in dementia the mechanism that generates paradigmatic responses becomes progressively less efficient (possibly due to a loss of semantic markers) and consequently more random (idiosyncratic) responses emerge. Perseverative responses, inhibited in normal subjects, are more prevalent in dementia. Anomic aphasics show a pattern of word associations similar to that of subjects with mild dementia. Broca's aphasics, while making fewer paradigmatic associations than normals, retain enough self-monitoring mechanisms so that few idiosyncratic and perseverative responses are made while more null responses occur. Wernicke's aphasics show a marked shift away from a paradigmatic word association strategy, possibly due to an inability to access semantic markers or a true loss of these markers. Metalinguistic deficits (i.e., a failure to adopt an appropriate strategy) may also contribute to this shift away from paradigmatic associations. Furthermore, a disruption of self-monitoring mechanisms in Wernicke's aphasia leads to an increase in perseverative and idiosyncratic responses.

Aged↗

PubMed1983

A case of subcortical dementia due to sarcoidosis of the hypothalamus and fornices.

A patient with sarcoidosis involving predominantly the hypothalamus and fornices was evaluated for dementia. He showed a relative sparing of fund of knowledge and orientation. Memory skills, particularly short-term memory, were severely impaired. Behavioral changes included apathy and a lack of spontaneity. Insight was relatively preserved. The pattern of his deficits showed some similarities to the pattern reported in patients with Huntington's disease and was different from that described in Alzheimer's disease. The dementia caused by subcortical pathology may differ in important respects from that caused by diffuse cortical dysfunction.

Adult↗